The subject matter disclosed herein relates to a system and method for on-line optical monitoring and control of a gas turbine engine.
Certain gas turbine engines include a combustor having viewports configured to facilitate monitoring of various interior surfaces of the combustor. For example, a pyrometry system may be in optical communication with the viewports and configured to measure the temperature of certain surfaces within the combustor. As will be appreciated, certain combustion products species, such as water vapor and carbon dioxide, absorb and/or emit radiation over a wide range of wavelengths. As a result, only a fraction of wavelengths emitted by the interior surfaces reach the viewports with sufficient intensity and negligible interference for accurate measurement. Consequently, certain pyrometry systems include sensors particularly configured to monitor wavelengths which are more likely to pass through the combustion products without significant absorption or interference. However, such sensors typically provide either a line-of-sight point temperature measurement or an average temperature measurement of each monitored surface.
Moreover, employing a two-dimensional detector array (e.g., a mid-wave infrared detector) to monitor surfaces within the combustor may not be effective due to interference from the combustion products. For example, the combustion products may absorb and/or emit radiation within a detectable wavelength range of the detector array. Accordingly, wavelengths emitted by the interior surfaces may not reach the viewports with sufficient intensity and negligible interference to be detected by the two-dimensional detector array.